Would it be more durable or efficient in any measurable way?
In theory at least they will be, yes, because angular bearings are better at taking non-axial loads . In practice I suspect the difference will be marginal if any, and angular bearings will need to have the preload set carefully. Setting the preload on Rotor 3D+ cranks isn't hard or difficult, but it will need to be done right or the angular contact bearings will eat themselves.
I'll go with the cheaper ones then I think. I don't need something that is unlikely to be much more reliable but more fiddly to set up which actually makes them less reliable.
In theory at least they will be, yes, because angular bearings are better at taking non-axial loads . In practice I suspect the difference will be marginal if any, and angular bearings will need to have the preload set carefully. Setting the preload on Rotor 3D+ cranks isn't hard or difficult, but it will need to be done right or the angular contact bearings will eat themselves.